The present invention relates generally to suspension struts in a vehicle and more particularly to a deflector seal used in a strut bearing assembly.
Passenger vehicles often have front suspension systems that use a strut to provide a damping assembly in parallel with a spring for ride comfort. The strut is attached between the body structure and the steering knuckle. As the steering knuckle rotates during a vehicle turning event, the rotation of the strut relative to the stationary body structure is carried through an integral bearing. The position of this bearing exposes it to the underbody conditions of water, grit and corrosive debris. A means of preventing intrusion of these contaminants into the bearing is required in order to prevent corrosion and ensure long term bearing durability.
Attempts to prevent intrusion into the strut bearing that have been used in the past include contacting lip seals, bearing shields and protective greases. Contacting lip seals are integral to the suspension bearing. These seals are normally molded or added elements that are integral to either the rotating or static portion of the bearing—outboard of the rolling elements. While effective at sealing, the static/dynamic characteristics of the sealing lips can present a parasitic drag (torque) that varies with loading or temperature that could be felt through the steering system.
Bearing shields are normally rigid elements that are non-contacting that reduce or shield the exposed area of the bearing opening. While effective at shielding direct contaminant and water exposure, the underbody dynamics of contaminants and water moving through the air create exposures that are beyond line-of-sight, which may allow for contaminants and water to enter the bearing.
Protective greases can be used. By filling the bearing with grease, this can prevent water and contaminant intrusion. However, the grease can create a parasitic drag on the bearing that is exacerbated by low temperatures as the grease becomes stiffer. Experience shows that the effectiveness of the grease can diminish over time as it becomes diluted with water and the contaminant content of the grease increases.